[PATCH v1 0/5] stop anon reclaim when zram is full

[Minchan Kim <minchan@kernel.org>]

For zram-swap, there is size gap between virtual disksize
and available physical memory size for zram so that VM
can try to reclaim anonymous pages even though zram is full.
It makes system alomost hang(ie, unresponsible) easily in
my kernel build test(ie, 1G DRAM, CPU 12, 4G zram swap,
50M zram limit). VM should have killed someone.

This patch adds new hint SWAP_FULL so VM can ask fullness
to zram and if it founds zram is full, VM doesn't reclaim
anonymous pages until zram-swap gets new free space.

With this patch, I see OOM when zram-swap is full instead of
hang with no response.

Minchan Kim (5):
  zram: generalize swap_slot_free_notify
  mm: add full variable in swap_info_struct
  mm: VM can be aware of zram fullness
  zram: add swap full hint
  zram: add fullness knob to control swap full

 Documentation/ABI/testing/sysfs-block-zram |  10 +++
 Documentation/filesystems/Locking          |   4 +-
 drivers/block/zram/zram_drv.c              | 114 +++++++++++++++++++++++++++--
 drivers/block/zram/zram_drv.h              |   2 +
 include/linux/blkdev.h                     |   8 +-
 include/linux/swap.h                       |   1 +
 mm/page_io.c                               |   6 +-
 mm/swapfile.c                              |  77 ++++++++++++++-----
 8 files changed, 189 insertions(+), 33 deletions(-)

-- 
2.0.0

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